Multiplying lever



Nov. 27, 1956 R. H. GRIEST 2,771,853

MULTIPLYING LEVER Filed Aug. 29 1955 INVENTQR. fbwm/a i/ixz Q if? .a.

United States Patent MULTIPLYING LEVER Raymond H. Griest, Los Angeles,Calif., assignor to Hughes Aircraft Company, Culver City, Calif., acorporation of Delaware Continuation of application Serial No. 327,555,December 23, 1952, now Patent No. 2,723,565, dated Novemher 15, 1955.This application August 29, 1955, Serial No. 531,122

1 Claim. (Cl. 116-114) This invention relates to mechanical indicatingmechanisms, and more particularly to a lever of the multiplying typesuitable, for example, for obtaining relatively large indications ofsmall motions of a movable or vibratory body.

This application is a continuing application of my application SerialNo. 327,555, filed December 23, 1952, now U. S. Patent 2,723,565 for aMultiplying Lever.

It has been found desirable in many instances to provide mechanicalmechanisms suitable, for example, for indicating the efiect on delicateparts, such as electrical measuring instruments, of vibratory motion ofa structure which supports such instruments. Such an indicatingmechanism may be employed, for example, to obtain data which may be usedto determine how the mounting of the structure may best be modified toinsure minimum vibrational movement thereof. Such an indicatingmechanism may also be employed to respond to physical movements of suchdelicate instruments by developing damping forces substantiallyinstantaneously upon the occurrence of such movements to react upon theinstrument thus reduce or damp undesired motions to a minimum. It isnecessary, under such circumstances, that the means employed formagnifying such small mechanical motions be free from backlash.

The present invention specifically relates to a simple leverconstruction including a pointer which will have relatively largephysical movement, with substantially no backlash, in response to verysmall motions of a movable body to which the lever is connected. Apreferred embodiment of a lever mechanism in accordance with thisinvention comprises a channel-shaped flexible element having flangesprovided with two coplanar flared portions. The two flared portions ofthe flanges are adapted to be secured, respectively, to a movablestructure and to a fixed reference structure. A pointer, which maycomprise a stiff wire, is bent intermediate its ends at an acute angleand has its ends secured to the opposite ends of the web of thechannel-shaped element. Upon motion of the movable structure within theplane of the flared portion of the flange aflixed thereto, the portionsof the flanges extending between the web and the flared portions will bedistorted so as to permit the web to rotate. The pointer moves with theweb and its intermediate portion moves over a relatively large distancecompared to the movement of the movable structure.

It is, therefore, an object of this invention to provide an extremelysimple lever of the multiplying type capable of magnifying small motionsof a portion thereof without backlash.

It is another object of this invention to provide a multiplying typelever comprising a pair of spaced, parallel, flexible elements adaptedto be secured, respectively, to a movable structure and to a fixedstructure, means providing mechanical linkage between the flexibleelements, and a pointer element aflixed to such linkage means andadapted to move through a relatively great distance in response. tosmall motions of the movable structure with respect to the fixedstructure.

It is a further object of this invention to provide a multiplying leverhaving a minimum number of component parts which is of simpleconstruction and capable of reliable operation for accurately magnifyingsmall motions of certain portions thereof.

The novel features which are believed to be characteristic of theinvention, both as to its organization and method of operation, togetherwith further objects and advantages thereof, will be better understoodfrom the following description considered in connection with theaccompanying drawing, in which difierent embodiments of the inventionare illustrated by way of example only, and the scope of the inventionis pointed out in the appended claim. In the drawing:

Fig. 1 is a perspective view of a simple lever construction inaccordance with this invention;

Fig. 2 is atop plan view of the lever of Fig. 1;

Fig. 3 is a perspective view smilar to Fig. 1, showing the action of thelever of the invention in response to a motion of a portion thereof;

Fig. 4 is a top plan view of the lever in the position shown in Fig. 3;

Fig. 5 is a top plan view of the lever of Fig. 1, in an arrangement toillustrate a practical use of the indicator of this invention;

Fig. 6 is a perspective view of a modified version of the lever of Fig.l; I

Fig. 7 is an exploded view showing the elements comprising the lever ofFig. 6; and

Fig. 8 is a side elevation of the lever of Fig. 6 illustrating itsposition in response to a small motion of a movable body to which it isconnected.

Referring to the drawing, in which like reference characters indicatelike elements throughout, and more particularly to Figs. 1 and 2, apreferred embodiment of the multiplying lever of this inventioncomprises a flexible, chanel-shaped member 10 having flanges 12, 14extending perpendicularly to or at right angles from a flat web orcenter portion 16. The channel member 10 may be formed from a sheet ofany suitable flexible material, such a phosphor bronze. The flanges 12,14 have flared ends shown, by way of example, as flat, flared sections18, 20 which flare or extend outwardly from the parallel portions offlanges 12, 14 in a common plane parallel to web 16. Affixed to theopposite ends of Web 16 is a pointer element 24. Pointer 24 preferablycomprises a wire that is bent in an acute angle at its center. The wirehas its free ends affixed to web 16 in a suitable manner, such as bysoldered connections provided at points 26, 28 at the corner between web'16 and flange 14. The pointer element could, of course, comprise atriangular sheet element having its base aflixed to web 16.

As indicated in Figs. 1 and 2, the flared sections 18, 20 of flanges 12,14 are adapted to be aflixed, respectively, to a fixed structure 30 andto a movable structure 32. As indicated by an arrow 33, movablestructure 32 is adapted for movement in opposite directions in the planeof flared section 20 and parallel to the edge of web 16. As will beexplained more fully hereinafter in connection with Figs. 3 and 4, thepointer 24, by virtue of the construction of the lever above described,will be moved in a plane parallel to flared section 20 and through aconsiderable angle in response to very small motions of movablestructure 32.

As will become more evident hereinafter, the flared sections 18, 20 areunnecessary to obtain wide movements of pointer 24 which correspond torelatively small motions of movable structure 32 in the manner abovedescribed. For example, flared sections 18, 20 could be eliminated andthe free ends of flanges 12, 14 extending perpendicularly from web 16scould .be ,secured, as by soldering, to the respectivestructures 30,32.

Figs. 3 and 4, illustrate motion of structure 32, a distanced withrespect.to.reference structure 30,:as indicated by arrow.'34,in theplaneofflared section'i20. In the..undistrted position of thechannel element10, shown in :dotted lines, the flanges 12, 14 tend to twist clockwise.at their front ends and counterclockwise attheir rear ends. Theflangesl2, 14 remainsusbtantially parallel, however, the web 16 and thetransverse center line 36,

which passes through the vertex or pointer end of pointer .24,rotatecounterclockwise .about an axis normal to the plane-of the web. Asindicated, fora motion of structure 32in the direction ofarrow'34,'which motion is :connterclockwise with reference to the.aforementioned :center line,'-web 16 and pointer.24 also rotatecounterclockwise. The actions-.above-described are opposite formotionstof-movable structure 32 opposite to arrow 34.

It can be shown that forvery small motions of movablesstructure 32 overa distanced, withrespect to reference structure 30,-and'for a web 16having a width w that is great compared to the distance d the free endof pointer 24 swings through an angle 6 given by:

Sin (i= .LU

Furthermore, for extremely small distances d, it may be :assumed thatsin 0-0 and hence:

Therefore, the movement of pointer 24 accurately cor- 'responds tothe'distance a through which movable structure 32 moves. The movement-ofpointer 24 magnifies the motion of movable structure'32 by a factordependent upon the distance d. The distance through which the end ofpointer 24 moves in response to a corresponding movement of structure 32through distance d depends upon the distance of the end of pointer 24from web 16.

Thus, with a sufficiently longpointer24, sufliciently large movementsmay be obtained which may be easily measured, in a suitable manner, todetermine the extent of the motion of structure 32 with respect toreference structure '30. Fig. -illustrates a preferred arrangement forobtaining an accurate measure of such movements.

Referring now to Fig. 5, the end of pointer 24 is employed as asliding-contact fora potentiometer resistor 40, which preferably iscurved to correspond to the arc through which the pointer moves. Theopposite ends of resistor '40 are connected to the positive and negativeterminals of a suitable direct-current voltage source 42. The junctionofthe potentiometer resistor 40 and the negative terminal of source 42 maybe connected to a point of reference potential, which is indicated asground.

An output voltage lead'44 is connected to pointer 24. Upon movement ofpointer 24 in response to movements of structure 32 in themannerpreviously described, vary- Accordingly,--voltage indications ofameasure of the, motion ofstructureffltor test purposes in the mannerpreviously indicated.

A second embodiment of a multiplying lever of the invention isillustrated in Figs. 6 through 8. Referring now to Figs. 6 and 7, arigidI-beam member 50, which consists of an elongated web portionfil anda pair of substantially cubical flanges 53, 55 atthe opposite ends ofweb 51, provides support for a pair of flexible-members ,52, 54.Flexible membersSZ, 54 are-equal in length to l-beam member 56 andextend between flanges 53,155 on opposite sides of elongatedweb 51.thereof. ,Flexible members 52, 54 are suitably secured at their endsto the flanges 53, 55 as, for example, bysuitable fastening means inaligned openings, so as to extend parallel tothe web 51 of the beam 50,in the manner indicated in Fig. 6. A pointer 24 is aflixed at its-endsto the flanges 53, 55 so as to extend perpendicularly from flexiblemember 54.

Centrally located between the ends-of"=flexible member 52 are oppositelyextending ortransverse finger sections 56, 57; similarly providedintermediate the ends of fiexible member 54 are oppositely extendingfinger sections 58, 59.

Referring now to Fig. 8, which illustrates the motion or distortion ofthelever of Figs. 6 and 7,finger sections '56, 57 are aflixed-to-areference or fixed structure 62 and the finger sections 58, 59 are atfixed to a movable structure 64. Upon motion of movable structure 64 inthe plane of finger sections 58, 59 of flexible member 64, as indicatedby arrow 65, flexible members 52, 54 are distorted. This distortiontakes the'form of counterclockwise twisting of the portions of flexiblemembers 52,-54 intermediate the respective finger sections'56, 57 and'58, 59 and the flanges 53, 55,so as to permit I-beam member 59 to turnslightly (counterclockwise in Fig. 8). *In the manner describedpreviously in connectionwith Figs. 2 and 3, the movement of pointer 24magnifies therelatively small motion of movable structure 64. Hence,pointer 24 moves through an angle 0 in response to motions of-movablestructure 64 through small distances d.

What is claimed is:

A multiplying lever comprising, in combination, a rigid I-beam memberhaving a narrow, elongated web portion extending between a pair ofrelatively wide flanges on opposite sides of said web portion, a pointerelement secured at two points to said flanges and having an intermediatepointed portion extending at right-angles to one of said flexibleelements, said one of said flexible elements being adapted forconnection intermediateits ends to a movable structure and the other ofsaidflexible elements being adapted to be'secured intermediate its endsto a reference structure, saidflexible elements distorting upon motionofsaid movable structure to permit rotation of said I-beam member aboutits longitudinal axis, said pointer being moved by said rotating I-beammember in a plane parallel tothe plane of movementof said movablestructure and through a distance tomagnify the movement of saidmovablestructure.

No references cited.

